Exhaust gas heat exchanger

Abstract

An exhaust gas heat exchanger including a stack of heat exchanger plates that form separate flow channels that run parallel to each other, collection spaces, and inlets and outlets for the exhaust gas and for the preferably liquid coolant. The flow channels for the one of the media formed from heat exchanger plates are longer than the flow channels for the other medium, and pass through the collection space for this other medium. The heat exchanger also includes a region without a housing in which the two flow channels run parallel to each other.

We claim:  
     
       1. A heat exchanger such as an exhaust gas heat exchanger comprising a stack of heat exchanger plates that form separate flow channels that run parallel to each other, with collection spaces, inlets and outlets for exhaust gas and for a coolant and characterized by the flow channels being formed from heat exchanger plates which, for one medium, are longer than the flow channels for the other medium and pass through at least one collection space for said other medium having the inlet and/or outlet; in that the region in which both flow channels run parallel to each other, the heat exchanger is designed without a housing; in that the collection space is bounded by two opposite tube sheets and enclosed by a jacket on which the inlet and/or outlet is situated; in that the jacket is formed by the edge of one tube sheet which forms a connection surface with the edge of the other tube sheet and by the outer channels being exhaust gas channels in which one tube sheet has an opening that has a cut-out in the corners for edge protrusions of the uppermost and lowermost heat exchanger plate in order to accommodate the entire stack of heat exchanger plates.